Heat-treatment-induced ferroelectric fatigue of Pt/Sr[sub 1-x]Bi[sub 2+y]Ta[sub 2]O[sub 9]/Pt thin-film capacitors.

The variations in the level of ferroelectric fatigue of Sr[sub 1-χ]Bi[sub 2+y]Ta[sub 2]O[sub 9] (SBT, 220-nm-thick) thin-film capacitors with Pt electrodes as a function of the heat-treatment temperature were investigated. The ferroelectric SBT thin films were spin coated on 200-nm-thick Pt/TiO[sub 2]/SiO[sub 2]/Si and crystallized by furnace annealing at 800 °C. The post-heat-treatment temperature of the Pt/SrBi[sub 2]Ta[sub 2]O[sub 9]/Pt capacitors was varied from 800 to 950 °C. The different post-heat-treatment temperatures barely affected the remanent polarization (P[sub r]) vs. the applied voltage (V[sub a]) characteristics (saturation P[sub r] of ∼ 10 µC/cm² at a V[sub a] of 5 V). However, the samples annealed at 900 and 950 °C showed serious ferroelectric fatigue after ∼10[sup 8]-10[sup 9] switching cycles whereas the sample annealed at 800 °C showed fatigue-free behavior up to 10[sup 10] cycles. This behavior appeared to have a close relationship with the loss of oxygen from the SBT layer during high temperature annealing. [ABSTRACT FROM AUTHOR]